Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2017
Frequency characteristics of pressure transducer kits with inserted pressure-resistant extension tubes.
The accurate monitoring of arterial blood pressure is important for cardiovascular management. However, the frequency characteristics of pressure transducer kits are influenced by the length of the pressure-resistant tube. To date, there have been few studies addressing the frequency characteristics of pressure transducer kits with inserted pressure-resistant extension tubes (pressure-resistant extension tube (ET) circuits). ⋯ For the ET210 circuit, the natural frequency and damping coefficient were 25.3 Hz and 0.180, respectively. As a result of extending the circuit, it was found that the natural frequency decreased drastically, while the damping coefficient increased slightly. When the extension of a pressure transducer kit is required, we should pay careful attention to the major decrease in the natural frequency, which may influence the pressure monitoring.
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J Clin Monit Comput · Apr 2017
Agreement in hemodynamic monitoring during orthotopic liver transplantation: a comparison of FloTrac/Vigileo at two monitoring sites with pulmonary artery catheter thermodilution.
To study agreement in cardiac index (CI), systemic vascular resistance index (Systemic VRI) and stroke volume variation (SV variation) between the FloTrac/Vigileo at radial and femoral arterial cannulation sites, and pulmonary artery catheter (PAC) thermodilution, in patients undergoing orthotopic liver transplantation. A prospective observational study of 25 adult patients with liver failure. Radial and femoral arteries were cannulated with standardised FloTrac/Vigileo arterial transducer kits and a PAC was inserted. ⋯ Agreement in SV variation between radial and femoral measurement sites approached a clinically acceptable threshold [mean difference (SD) 0.68 (2.44) %), LOA ±4.78 %]. FloTrac/Vigileo CI cannot substitute for PAC thermodilution CI, regardless of measurement site. SV variation measurements may be interchangeable between radial and femoral sites for determining fluid responsiveness.
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J Clin Monit Comput · Apr 2017
Can intracranial pressure be measured non-invasively bedside using a two-depth Doppler-technique?
Measurement of intracranial pressure (ICP) is necessary in many neurological and neurosurgical diseases. To avoid lumbar puncture or intracranial ICP probes, non-invasive ICP techniques are becoming popular. A recently developed technology uses two-depth Doppler to compare arterial pulsations in the intra- and extra-cranial segments of the ophthalmic artery for non-invasive estimation of ICP. ⋯ The correlation between invasive and non-invasive ICP measurements was good (R = 0.74), and the 95 % limits of agreements were -1.4 ± 8.8 mmHg. The within-patient correlation varied between 0.47 and 1.00. This non-invasive technique is promising, and these results encourage further development and evaluation before the method can be recommended for use in clinical practice.
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J Clin Monit Comput · Apr 2017
Practice patterns in the intraoperative use of bispectral index monitoring.
Assessing the depth of anesthesia and reducing intraoperative awareness has become a focus of much technology development and research in the field of anesthesia. Bispectral index (BIS) is the most widely utilized technology that uses electroencephalogram to provide a measurement of anesthetic depth. There are no definitive guidelines on when BIS should be used. ⋯ Factors associated with BIS use included increased age, greater ASA physical status, extremes of BMI, use of TIVA, use of a long-acting paralytic agent, use of an endotracheal tube (ETT), emergency surgery, increasing length of case, and certain surgical services. BIS use was associated with previously documented risk factors for intraoperative awareness. These factors are also indicators of case complexity, which may be a major factor among providers deciding when to apply BIS monitoring in the operating room.
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J Clin Monit Comput · Apr 2017
Comparative StudyEstimated continuous cardiac output based on pulse wave transit time in off-pump coronary artery bypass grafting: a comparison with transpulmonary thermodilution.
To evaluate the accuracy of estimated continuous cardiac output (esCCO) based on pulse wave transit time in comparison with cardiac output (CO) assessed by transpulmonary thermodilution (TPTD) in off-pump coronary artery bypass grafting (OPCAB). We calibrated the esCCO system with non-invasive (Part 1) and invasive (Part 2) blood pressure and compared with TPTD measurements. We performed parallel measurements of CO with both techniques and assessed the accuracy and precision of individual CO values and agreement of trends of changes perioperatively (Part 1) and postoperatively (Part 2). ⋯ During OPCAB, esCCO demonstrated poor accuracy, precision and trending ability compared to TPTD. Postoperatively, non-invasive esCCO showed better agreement with TPTD. However, invasive calibration of esCCO did not improve the accuracy and precision and the trending ability of method.